Q: It seems living in the Pacific Northwest is a health hazard due to lack of vitamin D. Not only have I been diagnosed with low vitamin D, practically everyone else I know also has this problem. Many of my irritating but nonsubstantial symptoms went away after getting my vitamin D level up to normal. I wish doctors had found it years ago. I think doctors should check it every time you visit.

A: The sunshine vitamin might well be in short supply in a climate dominated by clouds and rain. Even people who live in sunny places like Arizona or Florida can have low vitamin D levels, so getting tested is a very good idea.

Q: I am a midlevel prescriber (a clinical nurse specialist) who has submitted 37 adverse-event reports to the Food and Drug Administration's MedWatch program regarding generic lamotrigine. Most of the adverse events involved a loss of response, but many involved a loss of response and additional side effects that did not occur with brand-name Lamictal. The FDA has acknowledged receiving my reports, but it has not investigated them. When a generic for Lamictal first came on the market, I was enthusiastic. But after so many patients had serious relapses of their mood disorders or other bad experiences with several generic lamotrigine formulations, I am no longer enthusiastic. I believe the generic equivalents of Lamictal differ markedly in bioequivalence, enough so they may actually cause harm to patients. I worry that the problems with generics are more pervasive than we are willing to admit.

A: We, too, have received complaints about the generic form of Lamictal (lamotrigine). This anti-seizure drug also is prescribed for bipolar disorder. Here is just one example: "Has anyone else had problems with generic Lamictal? I have taken this for years for bipolar disorder, with great results. In the past few months, I have had a couple of terrible depressive episodes and thoughts of suicide. I wondered if the meds had just stopped working. Then I realized I was switched to the generic a couple of months ago." Others have reported problems with another generic epilepsy medicine, levetiracetam (brand name is Keppra).

Q: I had colon surgery last year, and as a result, I suffered from embarrassing, smelly flatulence. Fortunately, I found a product called Devrom (devrom.com). It has changed my life!

A: Stinky gas can be extremely embarrassing. Devrom contains bismuth subgallate. A similar compound, bismuth subsalicylate (Pepto-Bismol), is effective against odorous flatulence (Current Treatment Options in Gastroenterology, August 2001). It is possible to overdose on bismuth, so don't get carried away. Too much bismuth could harm the nervous system or kidneys. Pepto-Bismol also can interact with several medications.

In their column, Joe and Teresa Graedon answer letters from readers. Send questions to them via their Web site, peoplespharmacy.com.